The Bears' first organized team activity of the spring had the look and feel of an offseason practice, with technique, fundamentals and core schemes taking the stage as the main focus of the afternoon.
However, after watching the Bears run through drills and competitive team work Tuesday at Halas Hall, here's what I saw from Mel Tucker's defense as it began its introductory preparations to rebuilding that side of the ball.
New-look front: Watching the veteran free-agent signees, there is no question Tucker now has the creative flexibility to use multiple fronts.
Lamarr Houston has the movement skills, size and ability to play multiple spots to pair with the speed and power of Jared Allen off the edge. Plus, with the addition of defensive end Willie Young, the Bears have options — especially in the sub packages — to mesh that personnel in coverage and pressure schemes.
Tuesday was a classic first-day install session, with the Bears showing their base 4-3 "Over" and "Under" fronts. But once this defense get deeper in the playbook, there's opportunity to limit the running game and provide pressure in passing situations.
Jennings at nickel: With Tim Jennings' skill set and tackling ability, placing him in the nickel position is a smart move from Tucker to bump the veteran defensive back inside when the sub package is on the field.
Jennings is a physical player who can fill versus the run front and pressure off the edge, and he has the short-area change-of-direction speed to match an inside or outside release against a slot wide receiver.
I do believe first-round pick Kyle Fuller can play nickel, but given the demands and responsibility inside the numbers, aligning the rookie cornerback on the outside, where he can use the sideline as his help, allows the Bears to monitor his development this spring while maximizing Jennings' talent.
If Jennings starts the season inside, look for the veteran to be in position to make some impact plays versus the running and passing games.
Look of a pro: When you watch veteran safeties on the practice field, they demonstrate patience in their footwork and show the ability to identify concepts in the passing game.
That was Ryan Mundy on Tuesday versus quarterback Jay Cutler and the No.1 offense.
The free-agent pickup has the opportunity to win the starting job at strong safety, and he looked the part of a veteran who understands angles, leverage and technique.
With the Bears showing their base coverages (Cover-1, Cover-2), Mundy played some press man versus tight end Martellus Bennett and also rolled to the deep half in Cover-2 to put a tent on top of the defense. Mundy showed some athleticism and was quick with his run/pass keys to find the ball.
Rookie adjustments: While it's tough to evaluate rookies as they learn the playbook and begin their transition to the NFL, OTAs provide a baseline in terms of development.
Can they line up, make simple pre-snap adjustments, play the techniques of the huddle call and handle the tempo of a pro practice?
Tuesday was a good start for Fuller, Ego Ferguson, Will Sutton and Brock Vereen as they got their first taste of true NFL speed versus the veterans.
There is no question these rookies need work — and plenty of reps — to develop their technique, alignment, stance and leverage. However, tape of Tuesday's practice and the upcoming OTA sessions will provide them with valuable teaching tools to make corrections throughout the spring as they develop.
Special contributor Matt Bowen spent seven seasons in the NFL as a strong safety. He covers the NFL for Bleacher Report.